Despite recent advances in studies related to the inflammation process, methods for diagnosing and treating chronic inflammatory diseases have remained largely elusive. This is perhaps a result of the many and complex factors in the host that initiate and maintain inflammatory conditions. Current therapies have disadvantages associated with them, including the suppression of the immune system that can render the host more susceptible to bacterial, viral and parasitic infections. For example, use of steroids is a traditional approach to chronic inflammation treatment. Such treatment can lead to changes in weight and suppression of protective immunity. Advances in biotechnology have promoted the development of targeted biologicals with fewer side effects. To improve inflammatory disease treatment, technologies that alter and control the factors generated by cells of both innate and adaptive immunity systems need to be developed.
Host cells have surface receptors that associate with ligands to signal and regulate host cell activities. Administration of anti-TNF-α antibody or soluble TNF-α receptor has been shown to inhibit inflammatory diseases. Unfortunately, the side effects associated with this treatment can result in an increased risk of infections (e.g., tuberculosis) and other adverse reactions by mechanisms not fully understood. Similarly, antibody therapies focused on membrane bound molecules like CD40 have a propensity for inhibiting inflammation and graft-host diseases. While other targeted host cell therapies to prevent inflammatory diseases are being developed, there is no known single surface or secreted factor that will stop all inflammatory diseases. Consequently, the development of therapies to exploit newly identified specific host cell targets is required.
A variety of pathogens or toxins activate macrophages, neutrophils, T cells, B cells, monocytes, NK cells, Paneth and crypt cells, as well as epithelial cells shortly after entry into the mucosa. Chemokines represent a superfamily of small, cytokine-like proteins that are resistant to hydrolysis, promote neovascularization or endothelial cell growth inhibition, induce cytoskeletal rearrangement, activate or inactivate lymphocytes, and mediate chemotaxis through interactions with G-protein-coupled receptors. Chemokines can mediate the growth and migration of host cells that express their receptors. The cellular mechanisms responsible for the function of chemokines are often, but not entirely, Ca2+ flux dependent and pertussis toxin-sensitive. However, the precise mechanisms for chemokine-mediated events are not known.